cammander: state machine can now deny current state (e.g. when position lock lost during EASY mode), added FAILSAFE_STATE_LAND
commander, navigator: minor cleanup (refactoring), code style fixed
state_machine_helper: added missed transition to FAILSAFE_STATE_LAND, transition conditions fixed
commander: «home position set» condition fixed, failsafe fixes, navigator: state indication bugfix, control_mode fixes
commander, navigator: failsafe fixes, mavlink messages cleanup
Merge branch 'beta' of https://github.com/PX4/Firmware into beta